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Full-Text Articles in Physical Sciences and Mathematics
Exploring The Effects Of Biases In Mark-Recapture Fish Abundance Estimation With Software Simulations, Christian Yap
Exploring The Effects Of Biases In Mark-Recapture Fish Abundance Estimation With Software Simulations, Christian Yap
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Two-sample mark-recapture sampling is a common method used to estimate fish abundance. The idea is to capture and mark fish in an initial sample. The fish are then released to mix randomly with the whole population. A second sample is obtained, and the number of marked and unmarked fish is recorded. The Chapman estimator uses the number of fish marked in the first sample, the total number of fish captured in the second sample, and the number of recaptured fish to estimate abundance. The assumptions are: 1) the population is closed, meaning no immigration/emigration, and births/deaths occur, 2) all fish …
Using Gis To Analyze Graminoid And Shrub Composition Change From 1997 To 2017 At Atqasuk, Alaska, Rebecca Daigle
Using Gis To Analyze Graminoid And Shrub Composition Change From 1997 To 2017 At Atqasuk, Alaska, Rebecca Daigle
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Shrubs are expanding across the Arctic due to longer growing seasons and rapidly increasing air temperatures. Likewise, graminoid height is increasing. Changes in community composition may impact critical feedback loops and result in trophic cascades. Here, we analyzed vegetation cover change at a long-term research site in Atqasuk, Alaska. We compared cover across forty-eight, one-square-meter plots between 1997 and 2017. Shrubs and graminoids increased significantly over time, while bryophytes decreased over time. Other functional groups were inconsistent or showed no trend. We mapped the shrub and graminoid vegetation change in order to examine cover trends within the context of the …